Right-angle nerve-extractor.



A. FERNALD.

RIGHT ANGLE NERVE EXTRACTOR.

APPLICATION FILED JuLY 9.1915.

Patented Feb. 8, 1916.

gvwen/foz H. Tienen THB COLUMBIA PLANOGRAPH co., WASHINGTON. D. C.

llNlTFDf STATE@ PATENT FFllUlE.

ADELBEBT '.EERNALD, 0F BOSTON, MASSACHUSETTS.

rIEtIGri-I'.-AGELE NERVE--EXTRACTOR To all 'whom t may concern Be itknown that l, ADELBERT FERNALD, a citizen of the United States, residingat Boston, in the county of Suffolk and State of Massachusetts, haveinvented certain new and useful improvements in Right-AngleNerve-Extractors, of which the following is a specification. i i

The present invention relates to the art of dentistry and moreparticularly to a tool which can be used as a nerve extractor, rootcanal reamer or driller, andvwhich embodies novel features ofconstruction whereby the operator can work upon the back teeth withoutthe necessity of bending and flexing the tool, and can effectivelyoperate the tool by manual means.

Further objects of the invention are to provide a tcol of this characterwhich is comparatively simple and inexpensive in its construction, whichadmits of the various styles of tools being readily placed in positionor removed therefrom, which is light and compact in its construction sothat it can be easily handled and manipulated, and which can be readilyassembled and taken apart.

l/Vith these and other objects in view, the invention consists incertain novel combinations and arrangements of the parts as will morefully appear as the description proceeds, the novel features thereofbeing pointed out in the appended claim. y

For a full understanding of the invention reference is to be had to thefollowing de scription and accompanying drawing, in which Figure 1 is aside elevation of a dental tool constructed in accordance with theinvention, showing a nerve extractor point as fitted within the chuck.Fig. 2 is an enlarged vertical sectional view through the head of thetool. Fig. 3 is a similar view showing the manner of applying the lingerpiece to the main shaft. Fig. 4: is a horizontal sectional view taken onthe line fl-l of Fig. 2. Fig. 5 is an enlarged detail sectional view ofthe chuck, portions being broken away.

Corresponding and like parts are referred to in the followingdescription and indicated in all the views of the drawings by the samereference characters.

Specifically describing the present embodiment of the invention, thenumeral l Specification of Letters Eatent.

Patented Feb. 8, 1916.

Application filed July 9, 1915. Serial No. 33,994.

designates a tubular stock which has one end thereof exteriorly threadedat la, while the opposite end thereof projects into a looped handle 3which is secured to the sides of the stock. Extending through the tubirlar stock 1 and journaled therein is a main drive shaft L1, one end ofthe shaft having a small bevel gear 5 applied thereto, while theopposite end thereof projects beyond the stock 1 and has a cylindricalfinger piece or sleeve 6 rigidly applied thereto. The exterior surfaceof the cylindrical linger piece or sleeve 6 is preferably milled orroughened so that it can be readily grasped by the lingers and the smallset screw 7 is shown as provided for securing the finger piece to theshaft. This linger piece is positioned within the looped handle 3, andone end thereof is preferably reamed out at 6 so as to fit over the endof the stock 1 and obtain a bearing thereon.

A sleeve 8 is fitted upon the threaded end 1a of the stock 1, thediameter of the small bevel gear 5 being substantially the same as theexterior diameter cf the stock 1 so that the bevel gear 5 can beinserted through the bore of the sleeve 8. At the outer end of thesleeve 8 is a tubular head 9 which has the axis thereof arranged atright angles to the axis of the sleeve. A short tubular shaft 10 isjournaled within the head 9, and the upper end of the bore of the headis rea-med out or enlarged at 9a to provide a chamber for a bevel gear11 which is rigid with the tubular shaft 10 and normally meshes with thebefore mentioned bevel gear 5 at the end of the main shaft 4. A cappiece 12 is threaded within the mouth of the enlarged upper end 9a ofthe bore of the tubular head 9, said cap or plug being formed with acentral opening 12a to receive the upper end of the tubular shaft 1),and being also provided with a kerf 12b so that it can be readilyengaged by a screw driver or like tool when being placed in position orremoved therefrom.

A chuck 13 extends through the tubular shaft 10 and is formed with anaxial opening 14 adapted to receive the shank of a nerve extractor A orany similar tool. The lower end of the` chuck 13 terminates in a conicalenlargement 15 and is longitudinally slotted at 16, while the upper endthereof is threaded for engagement with a milled thumb nut 17. The boreof the tubular shaft 10 has the lower end thereof fiared at 10Ll forcoperation with the inclined walls of' the conical enlargement 15 at theend of the chuck 13 to force the jaws formed by the slot 16 into agripping engagement with the nerve extractor or like tool A when thechuck is drawn upwardly into the tubular shaft.

By loosening the thumb nut 17 the jaws of the chuck 13 will be permittedto spring apart a sufficient amount to admit of the shank of any form oftool A such as a nerve extractor, root canal reamer, or driller beinginserted into the bore of thev tubular shaft or Withdrawn therefrom.After the shank of the desired form of tool A has been inserted into thebore of the chuck 13 the thumb nut 17 is tightened so as to draw thechuck upwardly into the tubular shaft and cause the jaws thereof to beforced into a gripping engagement with the point by the cam actionbetween the flared mouth of the tubular shaft 10 and the conicalenlargement 15 at the slotted end of the chuck. When tightening thethumb nut 17 the cylindrical finger piece G is grasped between the fin-lgers so as to prevent rotation of the tubular shaft 10 and chuck 13 withthe thumb nut.

After the desired style of tool A has been inserted in the chuck, thedesired rotary movement can be imparted thereto by rolling thecylindrical finger piece 6 between the fingers of the hand. The loopedhandle 3 provides a convenient means for holding the tool in properposition while manipulat ing the same, and the working tool A isdisposed at right angles to the stock and handle so that the operatorcan work upon the back teeth without the necessity of fiere ing the toolin the usual manner. This is a great advantage, since a tool often hasto be bent at substantially right angles to the handle when being usedupon the back teeth and Copies of this patent may be obtained for` vecents each, by addressing the Gommssioner of Fatents,

under` these conditions the tool not infrequently breaks when rotated.

An important feature yof the hand operated right angle nerveextractor,root canal reamer and driller is that the chuck is so constructed thatit will hold any make, any size, and any length required ofbroaches,reamers, and drills. vVhen'using the drills and breaches" the tools maybe cut offI at suitable lengths before inserting them into the chuck.When the instrument is thus constructed, finebroaches, drills, andreamers can more readily follow the irregular nerve canal, without beingbroken, and this is very important, since, otherwise there would bedanger of drilling throiigh the sides of the root.

Having thus described the inventiomwhat I claim as new Aand desire tosecure by Letters Patent, is:#-

A dental drill of the including a tubular stock, a flat looped han dleprojecting longitudinally from one end of the tubular stock, a head uponthe opposite end of the tubular. stock, a main shaftV extendinglongitudinally through the tubular stock and Journaled therein, one endof the main shaft-projecting into the interior of the looped handle, afinger operated sleeve rigidly applied to the said end* of the mainshaft and arranged within the confines of the flat looped handle so asto be readily engaged by the fingers of the hand grasping the handle,and a chuck mounted within the head and geared tothe opposite end of'the main shaft.

In testimony whereof I affix my signature in the presence of twowitnesses.

ADELBERT FERNALD. Witnesses Sanna V. GILLIS, W. E. BOARDMAN.

Washington, D. C.

character described7`

